(2) can be done in two ways. Either you find a version of MinGW for Mac (I'm not a Mac user, so no idea where to get it) (which will include both some executables, and headers/libraries), OR you find MinGW for any other OS (e.g Windows versions are easier to come by) (which will include executables you can't natively run on Mac, but also the same headers/libraries) and then use a regular build of Clang (I'm not sure if Apple Clang is good for this, if not there's a way to get the normal non-apple version on Mac) like this:
clang++ --target=x86_64-pc-windows-gnu --sysroot=path/to/mingw.
